hull sanding

[Gary]

I have been doing a lot of research on sanding the bottom of a hull for more speed and there seems to be conflicting opinions on what to do. Some say a very fine finish 600-1200 and others say a rough finish 220 grit for really fast boats do to the fact that surface tensions are greater at higher speeds. Any thoughts on this.

[Heaving Earth]

It's been discussed over and over. There's no proof of anything either way.

[driftah]

I do mine with around the 400 to 600 range and it works at least a little as you will see the boat glide a little faster upon releasing the throttle, at speed Im not totally sure but most people I know do it. Just don't wax it lol

[Gary]

It's been discussed over and over. There's no proof of anything either way.

That's about what I have come up with as well, but thought I would ask .

[JimClark]

I personally doubt you will be able to see any difference

[Fluid]

I personally know that at least with some boats you will see a difference with 320 or 400 grit versus usuall painted/gelcoat bottoms - proven on both GPS and calibrated electronic timing equipment. Most folks just repeat BS they read somewhere.........




.

[Heaving Earth]

Lol oh well, I've tried it without any noticeable difference of a couple on boats. Plenty of bs on these forums tho

[driftah]

what u need is some advice from guys doing saw runs as because at their levels why wouldn't they do it? racers like brian buass, darin Jordan etc etc....if a hardcore saw guy that has proven results not doing it then we will see.

[martin]

Nothing scientific but I also noticed when coming off the throttle the boat deff appeared to glide further & stay on top off the water longer, I use 400-600 grit with front to back strokes.

[lenny]

I did that 400 grit to my Rio ep and hit 44 mph gps,
But I did not do it to the Pursuit yet,
That is next on the list as well as using one thumb screw to hold the hatch on with a seal.

[driftah]

Im with martin, when I first looked it up I payed attention to how my boat came in to shore when I let off throttle in glass waters prior,I had to let off the throttle around 50 percent earlier to glide in proper with a scuffed hull. Just my observation.....as for the high speed differences that is questionable but logic dictates it should

[Gary]

I only asked because I do not want to experiment to much more with my hull.I am pretty sure its just about done speed wise and do not want to go backwards at all. Right now its sanded with 400 grit but thought something more aggressive would benifit. Some times a mod will only show up at extreme speeds and not help with slower boats aswell...or the other way around....who knows.

[Gary]

I just did some testing and started with 400 grit and than dropped down to 150 grit and there was no difference at all that I could find using my data logger. I tried to make the test runs as equal as possible as well. So at least that's off the table for my particular hull.

[grsboats]

On my saw riggers the "speed finish" has helped to get the boats on plane quicker and as Martin well pointed out there is less drag to stop the boat SO we can expect some benefits from this procedure for some boats.Gill

[Gary]

I am wondering that mabe for really fast boats 100+ you need to have something even more aggressive than 150 grit....80-100 do to very fast water tension characteristics. Who knows.